Question

On the basis of chemical reactions involved, explain how do chloroflouorocarbons cause thinning of ozone layer in stratosphere.

Answer 1

Chlorofluorocarbons are stable compounds. They move to stratosphere by random diffusion. These undergo decomposition in the presence of sunlight to release Cl atoms. 

These Cl atoms cause catalytic chemical reactions and cause significant depletion of ozone layer as shown below:

Cl₂CF₂ → Cl  + C ClF₂

Cl + O₃ → ClO ∙ + O₂

ClO + O → Cl∙ + O₂

Since the free radicals use ozone and convert it to oxygen, they cause thinning of ozone layer in stratosphere.